Process for sulfonating halobenzene derivatives with sulfur trioxide

Abstract

A process for sulfonating at least one halobenzene with sulfur trioxide (SO 3 ) comprising the following steps: Step 1. manufacturing a gaseous mixture [mixture (M)] comprising SO 3 and at least one additional gas different from SO 3 by oxidizing sulfur dioxide in the presence of at least one catalyst, wherein the SO 3 content in mixture (M) is from 1 to 95% by volume, relative to the total volume of mixture (M); and step 2 contacting said mixture (M) with said at least one halobenzene.

The invention claimed is: 
     
       1. A process for sulfonating at least one monohalobenzene with sulfur trioxide (SO 3 ) comprising the following steps—:
 Step 1. manufacturing a gaseous mixture (M) comprising SO 3  and at least one additional gas different from SO 3 , by oxidizing sulfur dioxide (SO 2 ) in the presence of at least one catalyst, wherein the SO 3  content in the mixture (M) is from 1 to 95% by volume, relative to a total volume of the mixture (M)—; and 
 Step 2. contacting the mixture (M) with the at least one monohalobenzene. 
 
     
     
       2. The process according to  claim 1 , wherein in Step 1. the additional gas different from SO 3  is selected from a group consisting of air, nitrogen, carbon dioxide, oxygen, sulfur dioxide (SO 2 ), and mixtures thereof. 
     
     
       3. The process according to  claim 1 , wherein in Step 1. the mixture (M) comprises SO 3 , unconverted SO 2 , and air in which the SO 3  content is from 1 to 95% by volume, relative to a total volume of the SO 3 /air mixture. 
     
     
       4. The process according to  claim 1 , wherein in Step 1. the oxidation of SO 2  to SO 3  in the presence of the at least one catalyst is carried out in the presence of air, oxygen enriched air, neat oxygen, or oxygen-containing gases. 
     
     
       5. The process according to  claim 4 , wherein the SO 2  is mixed with preheated air to form a gaseous sulfur dioxide/air mixture (M SO2/air ). 
     
     
       6. The process according to  claim 5 , wherein in Step 1. the sulfur dioxide/air mixture (M SO2/air ) comprises from 0.1 to 30% of SO 2  by volume relative to a total volume of the mixture (M SO2/air ). 
     
     
       7. The process according to  claim 5 , wherein the sulfur dioxide/air mixture (M SO2/air ) comprises from 15 to 25% of O 2  by volume relative to a total volume of the mixture (M SO2/air ). 
     
     
       8. The process according to  claim 1 , wherein in Step 2. the mixture (M) is contacted with the at least one monohalobenzene without any preliminary separation or purification step of the mixture (M). 
     
     
       9. The process according to  claim 1  further comprising a molar ratio of SO 3 /monohalobenzene from 0.17 to 3 in Step 2. 
     
     
       10. The process according to  claim 1  further comprising in Step 2. feeding the at least one monohalobenzene into a reactor by one single batch addition at the start of the reaction, by sequential multiple batch additions, or by continuously feeding the at least one monohalobenzene into the reactor. 
     
     
       11. The process according to  claim 10 , wherein the at least one monohalobenzene is continuously fed into the reactor at a flow feeding rate equal to or less than 22000 liter per hour (l/h). 
     
     
       12. The process according to  claim 10  further comprising in Step 2. feeding the mixture (M) into the reactor at a flow feed rate equal to or less than 1500 liter per hour (l/h). 
     
     
       13. The process according to  claim 1 , wherein step 2 is carried out at a temperature of below 200° C. 
     
     
       14. The process according to  claim 1 , wherein step 2 is carried out at a pressure of below 10 atm. 
     
     
       15. The process according to  claim 1 , wherein the at least one monohalobenzene is monochlorobenzene (MCB). 
     
     
       16. The process according to  claim 2 , wherein the sulfur dioxide (SO 2 ) is unconverted SO 2 . 
     
     
       17. The process according to  claim 1 , wherein the process produces at least para-substituted halobenzene sulfonic acid compounds, 4,4′-dihalodiphenyl sulfones, and mixtures thereof. 
     
     
       18. The process according to  claim 1 , wherein the process produces at least para-chlorobenzene sulfonic acid, 4,4′dichlorodiphenyl sulfone, and mixtures thereof. 
     
     
       19. The process according to  claim 16 , wherein 96% to 98% of the SO 2  is converted to the SO 3  by oxidation. 
     
     
       20. The process according to  claim 1 , wherein more than 96% of the SO 2  is converted to the SO 3  by oxidation.